
x1, y1, x2, y2 = map(float,input().split())
r = ((x1-x2)**2+(y1-y2)**2)**.5
print("{:.8f}".format(r)) x1, y1, x2, y2 = map(float,input().split()) x1 map(float,input().split()) map float input().split() ().split () input split y1 x2 y2 r = ((x1-x2)**2+(y1-y2)**2)**.5 r ((x1-x2)**2+(y1-y2)**2)**.5 (x1-x2)**2+(y1-y2)**2 (x1-x2)**2 x1-x2 x1 x2 2 (y1-y2)**2 y1-y2 y1 y2 2 .5 print("{:.8f}".format(r)) print "{:.8f}".format(r) "{:.8f}".format "{:.8f}" format r x1, y1, x2, y2 = map(float,input().split()) map(float,input().split()) x1 x2, y2 = map(float,input().split()) map(float,input().split()) x2 y2 = map(float,input().split()) map(float,input().split()) y2 r = ((x1-x2)**2+(y1-y2)**2)**.5 ((x1-x2)**2+(y1-y2)**2)**.5 r y1, x2, y2 = map(float,input().split()) map(float,input().split()) y1

x1, y1, x2, y2 = map(float,input().split())
r = ((x1-x2)**2+(y1-y2)**2)**.5
print("{:.8f}".format(r))
